The present invention relates to drawer slides and more particularly to a telescopic frictional drawer slide.
Telescopic slides for file drawers and the like are often desirable for use in cabinets and other rack mounted applications. Such slides permit easy access to the interior of the drawer. The slides maintain the drawer in a horizontal position regardless of how far the drawer is withdrawn from the cabinet. The slides are also useful in the mounting of extendable shelves and cabinets. A typical drawer will often have two slides securing the drawer to the cabinet or enclosure, with the slides attached to each of the outside vertical walls of the drawer.
Frictional drawer slides typically have members that rub against each other in sliding engagement. One advantage of frictional drawer slides is that there are no ball bearings. One disadvantage of typical frictional drawer slides is noise of operation. Another disadvantage of typical frictional drawer slides is difficulty in opening because of a large amount of friction, especially after wear.
A telescopic drawer slide according to an embodiment of the present invention includes first, second and third drawer slides each having a longitudinal length with a web, and arms along the longitudinal margins of the web. The second drawer slide is nested within the arcuate arms of the first drawer slide. The third drawer is nested within the arcuate arms of the second drawer slide. The telescopic drawer slide has a lock between the second drawer slide and the first drawer slide, the lock having a biased tab rotatably coupled to the second drawer slide and an emboss on the first drawer slide. The tab moves into a portion of the emboss upon movement over the emboss, thereby preventing the second drawer slide from closing relative to the third drawer slide.
In an embodiment, the tab is biased by gravity. In an alternative embodiment, the tab is biased by a spring. The tab is moved over the emboss by the third drawer slide thereby allowing the second drawer slide to close relative to the first drawer slide after closing of the third drawer slide relative to the second drawer slide.
In an embodiment, the emboss has an angled portion tapering toward the arcuate arms of the first drawer slide, a wide portion with longitudinal edges, and an edge leading to a narrow portion. As the second drawer slide is withdrawn from the first drawer slide, the tab moves to the narrow portion and is restrained by the edge from closing.
The web of the second drawer slide has a hat section extending along the longitudinal length. The hat section of the second drawer slide clearing the emboss on the first drawer slide. The web of the third drawer slide has a hat section extending along the longitudinal length. The hat section of the third drawer slide clearing and surrounding the hat section of the second drawer slide.
In an embodiment, the arms of the first drawer slide have a lateral portion that is bowed toward the arms of the second drawer slide. The arms of the second drawer slide are nested within the arms of the first drawer slide defining a contact area along a tip of the bowed portion of the arms and a reservoir adjacent to the contact area.
In another additional embodiment, the arms of the third drawer slide have a lateral portion that is bowed toward the arms of the second drawer slide. The arms of the third drawer slide are nested within the arms of the second drawer slide defining a contact area along a tip of the bowed portion of the arms of the third drawer and a reservoir adjacent to the contact area.
In an additional embodiment, the telescopic drawer slide has a lock between the third drawer slide and the second drawer slide. The lock has a biased tab on the third drawer slide and a hole in the second drawer slide. The biased tab enters the hole when the third drawer slide is withdrawn from the second drawer slide.
In an alternative embodiment, the lock between the third drawer slide and the second drawer slide has a biased arm with a cutout rotatably coupled to the third drawer slide and a tab on the second drawer slide oriented toward the third drawer slide. The tab enters the cutout as the third drawer slide is withdrawn from the second drawer slide. In an additional embodiment, a lock release moves the biased arm to move the cutout away from the tab.
Additionally, a telescopic drawer slide according to an embodiment has a stop between the second drawer slide and the first drawer slide. A portion of the web of the second drawer slide is punched toward the first drawer slide and a portion of the vertical web of the first drawer slide is punched toward the second drawer slide.
In an alternative embodiment, the lock between the second drawer slide and the first drawer slide has a lever biased toward the first drawer slide coupled to the second drawer slide, a tab coupled to the lever, and a hole in the first drawer slide. The tab moves into the hole in the first drawer slide as the second drawer slide is withdrawn from the first drawer slide, thereby preventing the second drawer slide being closed relative to the first drawer slide. In an additional embodiment, a c-shaped tab is formed in the web of the third drawer slide. The c-shaped tab is biased toward the second drawer slide. The c-shaped tab moves the lever and the tab away from the first drawer slide allowing the second drawer slide to be closed relative to the first drawer slide member.
In yet another embodiment, the telescopic drawer slide has a detent. The detent includes a hole in the lever of the second drawer slide and a raised bump on the c-shaped tab of the third drawer slide. When the third drawer slide is closed within the second drawer slide, the bump fits inside of the hole in the lever. The detent prevents movement of the third drawer slide relative to the second drawer slide until a predetermined amount of force is used to pull the third drawer slide from the second drawer slide. The detent causes the second drawer slide to be withdrawn from the first drawer slide prior to the withdrawing of the third drawer slide from the second drawer slide.
A telescopic drawer slide according to an embodiment of the present invention fits within a space between a drawer and a cabinet of about 0.375 inches wide by about 1 inch in height.